Immobilized diluents for smoking articles

ABSTRACT

Immobilized diluents in a smoking article are provided, wherein diluents can be immobilized through absorption and/or adsorption of the diluents into immobilizing materials, such as sorbents like silica gels. By immobilizing diluents, the diluents can be available for vaporization, while still being protected from migration and/or loss of the diluents in a smoking article.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/793,537, filed Mar. 11, 2013, which is a divisionalapplication of U.S. patent application Ser. No. 11/812,028, filed Jun.14, 2007, now U.S. Pat. No. 8,393,333, issued Mar. 12, 2013, whichclaims benefit of the filing date of U.S. Provisional Application Ser.No. 60/835,090, filed Aug. 3, 2006, the entire contents of which areincorporated herein by reference.

BACKGROUND

Diluents can be added to smoking articles to alter the composition oftotal particulate matter (TPM) in tobacco smoke. However, the diluentscan be lost, can discolor tobacco cut filler and can change processingconditions for smoking mixtures. Thus, immobilized diluents are desiredwhich can circumvent the aforementioned issues.

SUMMARY

In an exemplary embodiment, an immobilized diluent comprises: a sorbent,wherein the sorbent comprises a porous material with a surface area ofat least 50 m²/g, and/or wherein the sorbent has a pore volume of about0.2 cc/g to about 1.5 cc/g, and a diluent absorbed and/or adsorbed inthe sorbent, wherein the diluent comprises an aerosol forming agent.

In another exemplary embodiment, a cigarette comprises: a filtercontaining a first sorbent material; a tobacco rod attached to thefilter; and immobilized diluents in the tobacco rod, wherein theimmobilized diluents comprise a second sorbent material with a porevolume of at least about 0.1 cc/g and diluent, wherein the diluentcomprises an aerosol forming agent.

In another exemplary embodiment, a method of reducing tar generated fromtobacco combustion, pyrolysis or distillation in tobacco smoke,comprises: heating a tobacco-containing portion of a smoking article;and releasing diluents immobilized within porous immobilizing particlesin a tobacco-containing portion of the smoking article by heating thediluents immobilized within the porous immobilizing particles, whereinthe released diluent alters the composition of the TPM in the tobaccosmoke.

In another exemplary embodiment, a method of making a cigarette,comprises: forming immobilized diluents by applying diluents to sorbentmaterials, wherein the diluents comprise aerosol forming agents; mixingthe immobilized diluents with tobacco cut filler; forming a tobacco rodfrom the tobacco cut filler with the immobilized diluents mixed therein;and attaching the tobacco rod to a filter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one mass unit of TPM without diluent compared to onemass unit of TPM diluted by diluent (50% TPM).

FIG. 2 is a graph comparing vapor pressure of selected diluents atdifferent temperatures.

FIG. 3 illustrates water absorption in exemplary immobilized diluents.

FIG. 4 illustrates an exemplary cigarette with immobilized diluentstherein.

FIG. 5 illustrates exemplary cigarettes and their corresponding samplecodes corresponding to the exemplary cigarettes and sample codes listedin Tables 3-15.

FIGS. 6A and 6B illustrate the TPM composition of exemplary cigarettes.

FIGS. 7A and 7B illustrate the TPM composition of exemplary cigaretteson a per puff basis.

DETAILED DESCRIPTION

Diluents can be used in smoking articles to alter the composition of thetotal particulate matter (TPM) of tobacco smoke. As the concentration ofinert diluents in TPM increases, the concentration of TPM produced bytobacco pyrolysis, combustion or distillation on a mass basis decreases.

The change in TPM concentration caused by diluents is illustrated inFIG. 1, which illustrates one mass unit of TPM without dilution comparedto one mass unit with dilution, wherein the diluted mass unit of TPM hasabout one-half of the TPM concentration. Thus, by providing diluents,TPM concentration can be reduced on a mass basis measurement. However,diluents can be lost to the environment or components of a smokingarticle due to their physical characteristics (i.e., because they areoften in liquid or vapor form and evaporate).

In order to reduce loss of diluents in a smoking article, immobilizeddiluents are disclosed herein. By providing diluents in an immobilizedform, the diluents can be protected from loss to the environment (e.g.,adsorption and/or absorption, hereinafter collectively “sorption”) or tocomponents of a smoking article.

A. Immobilization Of Diluents

As used herein, “immobilized diluents” are intended to include diluentswhich are substantially immobilized with reduced migration such that thediluents have reduced interaction with the environment and/or componentsof a smoking article. For example, immobilizing materials, such ashighly porous materials like sorbents (e.g., silica gels, zeolites,activated carbons, and/or polymeric porous materials) can be used toabsorb or adsorb diluents within their pores and surfaces.

As used herein, “highly porous” is intended to include materials withpore volumes exceeding about 0.2 cc/g. In exemplary embodiments, highlyporous immobilizing materials have pore volumes between about 0.2 cc/gand about 1.5 cc/g.

The quantity of diluents within exemplary immobilized diluents can bewidely varied depending upon the methods of forming the immobilizeddiluents, the weight and infusibility of the diluents, the weight andcapacity (i.e., the pore volume and surface area) of the containmentportion of the immobilizing material, etc. However, if the level ofdiluents added exceeds the capacity of the immobilizing material, excessdiluents may not be immobilized.

Exemplary immobilized diluents can be provided in particulate forms, andcan be round and/or spherical in shape. As used herein, the term“particulate” is intended to include discrete particles, granularsubstances, and/or powders.

Immobilized diluents can be any size provided that an effective level ofdiluent can be incorporated therein and the immobilized diluentparticulate can fit within the smoking article. In exemplaryembodiments, the diluents do not appreciably increase the size of theimmobilizing material; therefore the resulting immobilized diluents areabout the same size as the original immobilizing material. Immobilizeddiluents for cigarettes, for example, can have a transverse dimension inthe range of about 0.05 mm to about 2 mm.

The term “immobilizing material” is intended to include any materialthat can sufficiently absorb, adsorb, or hold diluents therein andsufficiently immobilize the diluents from diluent loss due toenvironmental factors, ageing, or sorption within a smoking device. Animmobilizing material, for example, can deter the migration of otherwisenon-immobilized diluent into components of a smoking article, andtherefore can extend the shelf lives of both the smoking article and thediluents. For example, cigarettes with activated carbon filters can haveshorter shelf lives as the diluents can deactivate the activated carbonand the activated carbon can remove the diluents from the cigarettes.

Additionally, immobilizing diluents can have other advantages. Forexample, by adding diluents directly to tobacco (without immobilizationof the diluents), tobacco rods formed from the diluent containingtobacco can suffer from “spotting” (i.e., discoloring of a cigarette),loss of firmness of a tobacco rod, and increased manufacturing costs(i.e., slower processes due to the difficulties caused by the diluentsin the tobacco during tobacco rod formation, such as tobacco being lessfree-flowing). Thus, by immobilizing diluents, these problems can besubstantially reduced, while the advantages provided by the diluents canstill be realized.

Exemplary immobilizing materials have high porosity to absorb and/oradsorb diluent therein. For example, pore volumes of at least about 0.1cc/g or between about 0.2 cc/g to about 1.5 cc/g and/or surface areas(as measured by BET, as discussed below) of at least about 50 m²/g orbetween about 100 m²/g to about 1000 m²/g can be used.

In exemplary embodiments diluents are infused or impregnated withinimmobilizing material. For example, immobilized diluents can be formedby placing sorbent materials within a vessel containing liquid and/orvaporous diluents, wherein diluents can be sorbed by the sorbentmaterials to immobilize the diluents. It is noted that the vessel canoptionally be pressurized and/or heated and held at that pressure and/orelevated temperature until the immobilizing material is sufficientlyinfused or impregnated with diluents to infuse or impregnate higherlevels of diluents if desired.

Alternatively, the immobilizing material can be placed in contact withdiluents to immobilize the diluents. For example, the immobilizingmaterial can be soaked in or coated by liquid and/or vaporous diluents,wherein the diluents are sorbed into the immobilizing material. Inexemplary embodiments, liquid and/or vaporous diluents are absorbedand/or adsorbed into pores of a highly porous sorbent material. Forexample, if the diluent comprises glycerin and/or propylene glycol, andthe immobilizing material is silica gel, the glycerin and/or propyleneglycol can be loaded into the silica gel at about 60% to 120 wt % of thesilica gel.

Additionally, the immobilized diluents can optionally be sealed with acoating to further immobilize the diluents. For example, a silica gelparticle can include glycerin therein, and can be coated by a thinpolymer layer, such as a polysaccharide, to further immobilize theglycerin.

In exemplary embodiments, the immobilizing materials and the immobilizeddiluents are non-combustible as to provide diluents from a stable,porous structure. As used herein, “non-combustible” is intended toinclude materials which will not be combusted at tobacco combustiontemperatures (i.e., up to about 1200° C.). For example, silica gel canremain stable and non-combustible up to temperatures of about 1200° C.However, it is noted that inert, combustible immobilizing material canalso be used.

B. Release Of Diluents

As used herein, “release of diluents” is intended to include mobilizingat least a portion of diluents from an immobilizing material such thatthe released diluents can interact with tobacco smoke. In order torelease the diluents from an immobilizing material, immobilized diluentscan be heated to: vaporize or aerosolize (hereinafter collectivelyreferred to as “vaporize”) the diluents into a more mobile state suchthat they are able to escape from the immobilizing material; or degradethe immobilizing material to form larger passages allowing diluents toescape from the immobilizing material.

In exemplary embodiments with diluents absorbed and/or adsorbed withinpores and channels of highly porous immobilizing material, the diluentsare released as they are heated because the diluents expand with theapplication of heat and are forced out of the pores and channels of theimmobilizing material. Thus, the diluents are vaporized and escape fromthe pores and channels of the immobilizing material and into mainstreamsmoke of a smoking article.

As used herein, “heated” or “heating” is intended to include elevatingthe temperature of an immobilized diluent to the point at whichvaporization of the diluent or thermal degradation of the immobilizingmaterial can occur. However, in exemplary embodiments, the immobilizingmaterial is non-combustible and remains stable throughout a smokingprocess.

Vaporization of the diluent or at least partial degradation of theimmobilized diluents occurs at elevated temperatures at or above aboutthe boiling points of the diluents. For example, immobilized diluentscan be placed within the tobacco and can release diluents when heated totemperatures between about 50° C. and about 900° C. (e.g., above 50° C.,100° C., 200° C., 300° C., 400° C., 500° C., 600° C., 700° C., 800° C.).

Exemplary diluents can be vaporized at temperatures at or above around180° C. For example, at a pressure of about 760 mmHg, the boiling pointof propylene glycol is about 190° C. and release of propylene glycol canbe expected at temperatures exceeding 190° C. Boiling point temperaturesfor exemplary diluents are discussed below and are set forth in Table 1.

C. Exemplary Diluents

The term “diluent”, as used herein, is intended to include any aerosolforming compound, material, or chemical, which can modify thecharacteristics of smoking articles and/or smoke produced when smokingthe smoking articles, or to alter the composition of the TPM of tobaccosmoke. Exemplary diluents are liquid or vaporous, chemically inert anddo not substantially change the taste or feel of the smoke.Additionally, exemplary diluents are not highly volatile, as highvolatility can lead to the diluents not being immobilized by theimmobilizing material.

Any appropriate diluent or combination of diluents may be containedwithin immobilizing material to form immobilized diluents, wherein thediluents can be released to modify the characteristics of the smokingarticles and/or smoke produced when smoking the smoking articles inwhich the immobilized diluents are incorporated.

For exemplary diluents, the amount of aerosols generated during smokingis dependent on their thermodynamic properties. Table 1 lists someexemplary diluents and their thermodynamic properties including boilingpoint, heat of vaporization, and heat capacity. Table 1 also lists theparameters of Antoine Equation for some compounds. Antoine Equation (asshown below) can be used to estimate the vapor pressure at a giventemperature, wherein P is the vaporization pressure, T is thetemperature, and A, B, and C are “Antoine coefficients” that vary fromsubstance to substance. FIG. 2 shows the vapor pressures of exemplarydiluents at different temperatures calculated using Antoine Equation(below).

${\log(P)} = {A - \frac{B}{T + C}}$

For low boiling point, high vapor pressure diluents, such as propyleneglycol (PG), immobilization can be especially effective to reduceotherwise high levels of loss due to evaporation or other environmentalfactors. For example, high levels of PG can be lost during ageing.

While any of the diluents listed in Table 1 can be used, glycerin,propylene glycol, triacetin, triethylene glycol, triethyl citrate, orcombinations thereof are preferred diluents.

TABLE 1 Thermodynamic properties of selected diluents B.P. at 760 V.P.at ΔH_(v) mmHg 180° C.¹ (J/mg) MW Cp Antoine Equ. Parameter (° C.) (bar)(J/mg) Formula (g/mol) (J/mg*K) A B C Propylene glycol² 188 0.754 0.94C₃H₈O₂ 76 0.00239 5.673 2418 −36.8 Ethylene glycol² 198 0.579 1.10C₂H₆O₂ 62 0.00242 5.019 1964 −79.3 Diethylene glycol² 245 0.127 0.58C₄H₁₀O₃ 106 0.00247 4.666 1895 −112.3 Triacetin² 259 0.213 0.39 C₉H₁₄O₆218 0.00180 8.802 4305 1.4 Ethyl laurate 269 0.39 C₁₄H₂₈O₂ 228 Diethylsuberate 282 0.27 C₁₂H₂₂O₄ 230 Triethylene glycol 285 0.034 0.53 C₆H₁₄O₄150 0.00220 6.757 3715 −1.3 Glycerin 290 0.022 1.00 C₃H₈O₃ 92 0.002393.937 1412 −200.6 Ethyl vanillate 292 C₁₀H₁₂O₄ 196 Triethyl citrate 2940.041 0.22 C₁₂H₂₀O₇ 276 3.883 1743 −122.4 Tributyrin 308 0.35 C₁₅H₂₆O₆302 0.00186 Diethyl sebacate 312 0.018 0.27 C₁₄H₂₆O₄ 258 5.822 3168−34.0 Benzyl phenyl acetate 320 C₁₅H₁₄O₂ 226 Benzyl benzoate 323C₁₄H₁₂O₂ 212 Erythritol 330 C₄H₁₀O₄ 122 Tetraethylene glycol 330 0.0060.51 C₈H₁₈O₅ 194 0.00218 8.200 4837 9.6 Ethyl stearate 354 0.52 C₂₀H₄₀O₂313 Dioctyl sebacate 420 0.22 C₂₆H₅₀O₄ 427 0.00199 ¹vapor pressure at180 degree Celsius was calculated based upon the Antoine Equation. ²TheAntoine Equation parameters of these compounds were not found in theliteratures; instead, the parameters were regressed from the vaporpressure data found in the literatures.

Alternatively or additionally, immobilized diluents can includeadditives, such as humectants, flavorants, solvents, etc., immobilizedin immobilizing material. For example, suitable additives includechemicals that can aid in the delivery of flavor, provide moisture tomainstream smoke, or deliver flavors via the particulate phase ofmainstream smoke (bypassing sorbents in a smoking article). Exemplaryadditives include, but are not limited to, sorbitol, water, menthol,etc.

D. Exemplary Immobilizing Materials

Exemplary immobilizing material preferably have the followingcharacteristics:

1) sufficient diluent carrying capacity, such that sufficient amounts ofdiluents can be provided within the immobilizing material;

2) suitable decomposition or release properties, such that theimmobilizing material can be heated to combust or decompose theimmobilizing material at approximately the same rate as the smokingarticle, or can release the diluent from the immobilizing material uponprovision of heat;

3) suitable robustness or strength, such that the immobilizing materialcan withstand physical forces, such as those associated with loading theimmobilized diluents within a smoking article, without breaking orreleasing diluents from the immobilizing material; and

4) appropriately small sizing, such that the immobilizing material withthe diluents therein can fit within a smoking article without disturbingthe characteristics of the smoking article, such as the diameter of atobacco rod of a cigarette.

Exemplary immobilizing materials include, but are not limited to,sorbents. As used herein, a “sorbent” is a substance that has theability to condense or hold molecules of diluents and/or one or moretobacco smoke constituents on its surface, and/or has the ability totake up such components, i.e., through penetration into its innerstructure or into its pores. The term “sorbent” as used herein refers toan adsorbent, an absorbent, or a substance that can function as both anadsorbent and an absorbent.

The term “sorption” is intended to encompass interactions on a sorbentsurface and within pores and channels of sorbents, such as silica gels,molecular sieves, activated carbons, polymeric porous materials, and/ormixtures thereof. Thus, diluents would be subjected to sorption by asorbent as a means of immobilizing the diluent within the sorbent.

Exemplary shapes for the immobilizing materials include particulate,spheres, amorphous shapes, rods, blocks, etc., wherein the transversecross-sectional areas can have any shape, such as circular, triangular,square, etc. For example, discrete particles that are freely flowing, orin the alternative, particulate formed by shredding sheets ofimmobilizing material can be used. If discrete particles are used, theparticles can be sized from about 0.001 mm to about 3 mm. For example,particles sized from about 0.05 mm to about 2 mm can be used to providedesirable air flow (i.e., resistance to draw) and sorptioncharacteristics.

One type of sorbent, activated carbon, as used herein, can bemanufactured by any suitable technique. One technique is thecarbonization of coconut husk, coal, wood, pitch, cellulose fibers, orpolymer fibers, for example. Carbonization is preferably carried out athigh temperatures, i.e., 500-900° C. in an inert atmosphere, followed byactivation under oxidizing conditions. The activated carbon can be usedin the forms of monolithic shapes, granules, beads, powders and/orfibers. If desired, the activated carbon can be incorporated in anothermaterial such as paper.

Activated carbon may include a distribution of micropores, mesopores andmacropores. The term “microporous” generally refers to such materialshaving pore sizes of about 20 Å or less while the term “mesoporous”generally refers to such materials with pore sizes of about 20 to 500 Å.The term “macroporous” refers to pores with pore sizes above 500 Å. Therelative amounts of micropores, mesopores and macropores can be selectedto immobilize diluent therein as an immobilizing material.Alternatively, activated carbon provided in filters of cigarettes forsorption of tobacco smoke constituents can be selected relative to thesizes of molecules of selected components from mainstream tobacco smokethat are to be targeted and removed. Thus, the pore sizes and poredistribution can be adjusted accordingly as needed for certainapplications.

Another material which may be used as a sorbent is a molecular sievezeolite. The term “molecular sieve” as used herein refers to a porousstructure composed of an inorganic silicate material. Zeolites havechannels or pores of uniform, molecular sized dimensions. There are manyknown unique zeolite structures having different sized and shapedchannels or pores. The size and shape of the channels or pores cansignificantly affect the properties of these materials with regard tosorption and separation characteristics.

Zeolite-type molecular sieves include ZSM-5, A, X, and Y-type zeolites,as well as silicoaluminophosphates and mesoporous molecular sieves, suchas MCM-41, MCM-48 and SBA-15. These can be granular materials. Thisfamily of materials contains regular arrays of uniformly-sized channelsand tunable internal active sites, and can admit molecules below acertain size into their internal space. Microporous, mesoporous and/ormacroporous molecular sieves may be used.

Silica gels can also be used as sorbents. One example is thecommercially available Davisil granular silica gels (manufactured byGrace Davison of Columbia, Md.) with average pore size of 40 angstroms,60 angstroms, 90 angstroms and 150 angstroms. The particle size of theDavisil granules is about 35×60 mesh (i.e., a range of particle sizesfrom about 0.25 mm to about 0.5 mm in transverse dimension).

The porosity of the sorbents can be measured by Argon adsorptionisotherms for example. The Argon adsorption isotherms of these silicagel samples can be measured using a Micromeritics AdsorptionPorosimeter, wherein the BET (Bruner, Emmett, and Teller) specificsurface areas and pore size distributions can be calculated based uponthe isotherms.

Exemplary loading of diluents on silica gels are shown in Table 2 below.For Table 2, silica and diluent are in a sealed container and placed ina convection oven at a temperature of 70° C. for 15 hours, wherein thesealed containers were periodically removed from the oven, mixed andplaced back into the oven during heating to fully impregnate andimmobilize diluent in the silica gel. After this impregnation andimmobilization process, the particles of some samples were found to nolonger be free flowing due to the excessive loading of the liquiddiluents. The maximum loading was determined by the sample whichcontained the highest diluents loading among the free-flowing samples.The BET specific surface areas, pore volumes and maximum loading (in wt% silica) of glycerin (GLY) and propylene glycol (PG) for theseexemplary silica gels are listed in Table 2.

TABLE 2 Adsorption capacity of exemplary silica gels Average pore size(Å) 40 60 150 Pore volume (cc/g) 0.65 0.75 1.10 BET specific area (m²/g)675 480 300 Max gly. loading (wt % of silica) — 80% 120% Max PG loading(wt % of silica) — 67% 100%

Table 2 shows that the pore volume increases and the BET specificsurface area decreases as the average pore size increases. For thesamples of Table 2, silica gel with average pore size of 150 Å was usedfor testing because of its high loading capacity, wherein the loadingcapacity of a given silica gel is directly related to the pore volume,wherein the larger the pore volume, the higher the loading capacity ofthe silica gel.

While not wishing to be bound by theory, it is believed that glycerinabsorbed by the silica gels listed in Table 2 has a higher weightloading than that of propylene glycol due to the higher density ofglycerin (the density of glycerin is about 1.25 g/cc whereas the densityof propylene glycol is about 1.05 g/cc). It is further noted that themaximum volumetric loadings of glycerin and propylene glycol are aboutthe same.

Exemplary immobilized diluents absorb moisture in that both theimmobilizing material and the diluents can both tend to absorb moisture(i.e., hygroscopic), thus the immobilized diluents can be prone toabsorb moisture. In an exemplary embodiment, glycerin- andPG-impregnated silica are shown to absorb moisture during ageing. In anexemplary embodiment, Davisil 646, 150 Å pore size silica gels werepre-impregnated with 110 wt % and 100 wt % glycerin and PG,respectively. The impregnated samples were exposed to the atmospherewith a controlled humidity of 55%, wherein the percent weight gain(mostly due to the uptake of moisture) was monitored daily. Asillustrated in FIG. 3, the percent weight gain over time, which wasmeasured as the water uptake on the diluent impregnated silica,stabilized at about 1% for the silica and about 5% for bothglycerin-impregnated and PG-impregnated silica gels at a room humidityof 55% and a temperature of 20° C.

It is noted that sorbent mixtures can also be used to providecombinations of immobilization properties of diluents and/or filtrationcharacteristics to immobilize diluents and/or achieve a targetedfiltered mainstream smoke composition, if desired.

E. Smoking Articles

It is envisioned that immobilized diluents may be used in smokingarticles. The term “smoking articles” is intended to include elongatedsmoking articles, such as cigarettes and cigars. Non-traditionalcigarettes such as cigarettes for electrical smoking systems are alsoincluded in the definition of smoking articles or cigarettes generally.

The amount of immobilized diluents in smoking articles can be selectedby balancing the level of diluent effects with the mass of the smokingarticles such that the taste and feel of the smoking articles are notsubstantially changed by the addition of immobilized diluents. Inexemplary embodiments, between 1 and 300 mg or between 50 and 150 mg ofimmobilized diluents (including both the immobilizing material and thediluents) can be used in a cigarette, which can have about 500-700 mg oftobacco filler therein. It is noted that the level of diluent is limitedby the combustibility of the tobacco with the immobilized diluentstherein. For example, about 1 to about 40 wt % diluent or about 10 toabout 30 wt % diluent can be included within an exemplary cigarette,such that sufficient levels of tobacco are present to allow continuouscombustion of the tobacco in the cigarette.

Immobilized diluents can be provided in tobacco filler. By providingimmobilized diluents in tobacco filler, the immobilized diluents can beheated by combustion of the tobacco and the diluents can be releasedfrom the immobilizing material.

Exemplary smoking articles, as illustrated in FIG. 4, can be used withimmobilized diluents 410. As illustrated in FIG. 4, a cigarette 400 cancontain two sections, a tobacco-containing portion sometimes referred toas the tobacco or cigarette rod 430, and a filter portion 450 withsorbent 220 located between and/or surrounded by filter material 440,such as cellulose acetate (CA). The filter portion can be surrounded bytipping paper, which forms a mouth end of the cigarette. The tippingpaper can overlap with the tobacco rod in order to hold the filter andtobacco rod 430 together. The tobacco rod 430, or tobacco containingelement of the cigarette, can include immobilized diluent mixeduniformly or non-uniformly within tobacco filler, as discussed above.Additionally, a paper wrapper surrounding the tobacco rod 430 can beprovided, wherein an adhesive can be used to hold the seams of the paperwrapper together.

In the exemplary cigarette 400 of FIG. 4, the sorbent 420, which can bethe same or different from the immobilizing material sorbent, isincluded in a filter of the cigarette 400. By including sorbent insmoking articles, levels of targeted constituents of mainstream smoke,such as benzene, acrolein or 1,3-butadiene can be reduced; however,levels of non-targeted constituents, such as natural flavor constituentsor diluents added directly to tobacco filler for their aerosol formingproperties, can also be reduced due to the adsorption by the sorbent. Byproviding diluents within immobilizing material, diluents can beprovided in an isolated manner from the sorbent during storage (or priorto release from the immobilizing material) thus reducing sorption ofdiluents by the sorbent during storage.

The term “smoking” is intended to include the heating, combusting orotherwise causing of a release of certain chemicals from tobacco.Generally, smoking of cigarettes involve lighting one end of a cigaretteand drawing mainstream smoke downstream through a mouth end of thecigarette. Alternatively, smoking of non-traditional cigarettes or othersmoking articles may be smoked by other means.

The term “mainstream smoke” includes the mixture of gases and/oraerosols passing down a smoking article, such as a tobacco rod, andissuing from an end, such as through the filter end, i.e., the smokeissuing or drawn from the mouth end of a cigarette during smoking of thecigarette. It is noted that in a cigarette, for example, the mainstreamsmoke contains air that is drawn in through the heated region of thecigarette and through a paper wrapper surrounding the cigarette.

A non-traditional cigarette typically contains the same two sectionswith a tobacco-containing portion (tobacco rod) and a filter portion.However, unlike a traditional cigarette wherein the tobacco rodcomprises cut filler, the tobacco-containing portion of anon-traditional cigarette includes a tobacco plug of cut filler wrappedwithin a tobacco mat. Typically, the tobacco mat includes tobaccotherein, and is used to form a hollow tube around the tobacco plug,wherein the tobacco mat is heated by heating blades of a non-traditionalcigarette smoking system.

Non-traditional cigarettes include, for example, cigarettes forelectrical smoking systems as described in commonly-assigned U.S. Pat.Nos. 6,026,820; 5,988,176; 5,915,387; 5,692,526; 5,692,525; 5,666,976;and 5,499,636, the disclosures of which are incorporated by referenceherein in their entireties. In an exemplary embodiment, the immobilizeddiluents can be provided within the tobacco-containing portion (tobaccorod) of a non-traditional cigarette, and can operate in a manner similarto traditional cigarettes.

In the filter portion of a traditional or non-traditional cigarette,sorbents can be incorporated for the sorption of targeted tobacco smokeconstituents. As mentioned above, these sorbents can be the same ordifferent from the sorbents used as immobilizing material. For example,the sorbent can be activated carbon, zeolite, other molecular sieves,polyaromatic resins (e.g., PMMA, benzene type resins, phenolic resins,microsponges and super-absorbents), sorbents located in fibrous filtermaterial, or combinations thereof.

Sorbent can be incorporated in a cigarette filter at one or more desiredlocations. For example, a sorbent segment, such as sorbent particulatein a cavity or sorbent in filter material (e.g., carbon-on-tow), can becombined with a free-flow filter. The sorbent can be in contact with(i.e., abut) a free-flow filter positioned between the free-flow filterand a mouthpiece filter plug or in contact with (i.e., abut) amouthpiece filter plug. The sorbent segment can have a diametersubstantially equal to that of the outer diameter of a free-flow filterto minimize by-pass of smoke during the filtration process. The filtercan also include a sorbent in oriented or non-oriented fibers and asleeve, such as paper, surrounding the fibers.

Fibrous sorbent-containing filter segments can have a high loft with asuitable packing density and fiber length such that parallel pathwaysare created between fibers. Such structure can effectively removeselected gas-phase constituents, such as formaldehyde and/or acrolein,while removing minimal amounts of particulate matter from the smoke,thereby achieving a significant reduction of the selected gas-phaseconstituents, while not significantly affecting the TPM in the tobaccosmoke. A low packing density and a short fiber length can be used toachieve such filtration performance.

The amount of sorbent used in filters in exemplary embodiments of thesmoking article depends on the type and the amount of selected gas-phaseconstituents in the tobacco smoke.

Examples of suitable types of tobacco materials that can be used in asmoking article including immobilized diluents include, but are notlimited to, flue-cured tobacco, Burley tobacco, Maryland tobacco,Oriental tobacco, rare tobacco, specialty tobacco, blends thereof andthe like. The tobacco material may be provided in any suitable form,including, but not limited to, tobacco lamina, processed tobaccomaterials, aged tobacco such as volume expanded or puffed tobacco,processed tobacco stems, such as cut-rolled or cut-puffed stems,reconstituted tobacco materials, blends thereof, and the like. Tobaccosubstitutes may also be used.

In traditional cigarette manufacture, the tobacco is normally used inthe form of cut filler, i.e., in the form of shreds or strands cut intowidths ranging from about 2 mm to about 1 mm or even about 0.5 mm. Thelengths of the strands range from between about 5 mm to about 80 mm. Anexemplary cigarette can include between about 300-750 mg of tobacco,preferably around 550 mg for a standard cigarette. The cigarettes mayfurther comprise one or more flavors, or other suitable diluents (e.g.,burn diluents, combustion modifying agents, coloring agents, binders,etc.).

F. Example

In an exemplary embodiment, exemplary activated carbon containingcigarettes, similar to those illustrated in FIG. 4, with tar values of11-mg and 6-mg are provided. These exemplary cigarettes include a 49 mmtobacco rod and a 34 mm filter rod and optionally an 8 mm of activatedcarbon beads in a plug-space-plug configuration, as illustrated in FIG.5.

Glycerin-impregnated silica gel (the silica gel being referred to inthis example generally as “silica”) with maximum glycerin loading (madefrom a 12:10 glycerin to silica weight ratio) is provided within thetobacco rod of the exemplary cigarettes. Eight samples are constructedby adding either 110 mg or 220 mg of glycerin-impregnated silica gelinto the tobacco rod of the exemplary cigarettes. The weight of tobaccofiller was fixed at 550 mg for all the exemplary cigarettes.Illustrations of the exemplary cigarettes, as prepared, and theircorresponding sample codes are shown in FIG. 5 and some of the resultsof testing are listed in Tables 3-15.

Table 3 lists the results of puff count, TPM, tar, nicotine, water,glycerin and percent glycerin transfer corresponding to the exemplarycigarettes and their sample codes illustrated in FIG. 5.

TABLE 3 TPM, tar, water, nicotine, glycerin and percent glycerintransfer TPM¹ Tar² Nicotine Water Glycerin Smoke Glycerin Cig. Puff (mg/(mg/ (mg/ (mg/ (mg/ Tar⁴ (% Cigarette Code Cigarette Description Countcigt) cigt) cigt) cigt) cigt) (mg/cigt) Trans.) 11-mg A-01 Control (8 mmC-Beads in 6.2 11.40 9.40 0.74 1.28 1.06 8.34 4.24 tar A-02 110 mg(Silica + glycerin) in filler 8.2 14.00 11.20 0.74 2.10 4.78 6.42 6.62A-03 220 mg (Silica + glycerin) in filler 9.7 13.90 11.10 0.63 2.17 7.014.09 4.83 A-04  50 mg (Silica only) in filler 7.2  9.10 7.40 0.64 1.060.94 6.46 3.76 A-06 100 mg (Silica only) in filler 8.5  8.40 6.90 0.680.89 0.87 6.03 3.48 A-06 110 mg (Silica + glycerin) in filler, no 8.418.00³ 14.10 0.88 3.02 3.16 10.95 3.71 carbon and empty cavity in filterA-07 220 mg (Silica + glycerin) in filter, no 10.2 12.93³ 10.12 0.682.13 3.62 6.60 2.50 carbon and empty cavity in filter A-08 110 mg(Silica + glycerin) in filler, 8.7 13.97 11.16 0.72 2.09 2.34 8.82 2.76carbon replaced by CA A-09 220 mg (Silica + glycerin) in filler, 9.813.30 10.72 0.65 1.93 3.09 7.63 2.13 carbon replaced by CA  6-mg B-01Control (8 mm C-Beads in 6.7  6.10 4.00 0.74 1.28 0.63 3.37 2.52 TarB-02 110 mg (Silica + glycerin) in filler 9.7  5.70 4.60 0.37 0.75 1.383.22 1.62 B-03 220 mg (Silica + glycerin) in filler 11.3  4.60 3.60 0.280.69 1.65 1.95 1.14 B-04  50 mg (Silica only) in filler 8.0  4.60 3.700.36 0.61 0.49 3.21 1.96 B-05 100 mg (Silica only) in filler 8.9  3.502.80 0.27 0.40 0.39 2.41 1.56 B-06 110 mg (Silica + glycerin) in filler,no 9.9  6.10 5.00 0.37 0.72 1.04 3.96 1.22 carbon and empty cavity infilter   B-07 220 mg (Silica + glycerin) in filler, no 12.1  4.67 3.780.26 0.62 1.05 2.73 0.72 carbon and empty cavity in filter   B-08 110 mg(Silica + glycerin) in filler, 9.3  4.93 4.04 0.30 0.59 0.93 3.11 1.09carbon replaced by CA   B-09 220 mg (Silica + glycerin) in filler, 11.8 4.17 3.40 0.24 0.64 0.83 2.57 0.57 carbon replaced by CA   ¹TPM numberslisted here were collected in the experiments for the analyses of tar,nicotine and water. TPM used for the measurement of glycerinconcentration were collected in separate experiments and are not listedin the table. ²Glycerin is included in tar. ³The difference between theTPM here and the TPM obtained in the experiments for the glycerinanalysis is statistically significant. ⁴Smoke tar is equal to tar minusglycerin.

Results showed that for both 11-mg tar and 6-mg tar cigarettes, the puffcount increases when either plain silica or glycerin-impregnated silicaare added into the tobacco rod. Since silica does not combust, theincreased puff count seems to indicate that the smoldering rate isreduced due to the presence of silica. The puff count, which is thenumber of puffs taken on a cigarette smoked to a prescribed butt lengthunder standardized smoking conditions, appears to be further increasedwhen glycerin-impregnated silica is added into the tobacco rod. This maybe attributed to an increased total combustible mass (i.e., tobacco andglycerin) in the tobacco rod.

The addition of plain silica in the tobacco rod decreased the TPM forboth 11-mg tar and 6-mg tar cigarettes in spite of the fact that itincreased the puff count.

It is believed that when the glycerin is in the tobacco rod immobilizedby silica, a combination of two competing effects on TPM is expected:the first, increased TPM due to the presence of glycerin; and thesecond, decreased TPM due to the presence of silica. As a result oftesting, an increase in the TPM is observed for the 11-mg tar exemplarycigarettes whereas a small decrease in TPM is observed for the 6-mg tarcigarette. While not wishing to be bound by theory, it appears that asthe ventilation increases (with the lower tar content cigarette), theincrease in the TPM level due to the addition of glycerin in the tobaccorod is reduced, and therefore the decrease of TPM due to the presence ofsilica in the tobacco appears to become more significant.

Table 3 lists the percent of glycerin in the tobacco rod transferredinto the mainstream smoke. The tobacco filler used in the exemplarycigarettes contained about 30 to about 150 mg of glycerin, which can beused to achieve about 0.5 to about 5.6% transfer of glycerin in theexemplary control cigarettes. The listed percent glycerin in the tobaccorod transferred into mainstream smoke was calculated using the followingequation:

${\%\mspace{14mu}{Transfer}} = {\frac{{{Wt}.{\mspace{11mu}\;}{of}}\mspace{14mu}{Diluent}\mspace{14mu}{in}\mspace{14mu}{TPM}}{\;{{{{Wt}.\mspace{14mu}{of}}{\mspace{11mu}\;}{Diluent}{\mspace{11mu}\;}{in}\mspace{14mu}{Silica}} + {{{Wt}.{\;\mspace{11mu}}{of}}\mspace{14mu}{Diluent}\mspace{14mu}{in}{\mspace{11mu}\;}{Tobacco}}}} \times 100}$

The compositions of the TPM for the exemplary cigarettes are alsographically illustrated in FIG. 6A (sample codes starting with “A”indicating 11-mg tar exemplary cigarettes) and FIG. 6B (sample codestarting with “B” indicating 6-mg tar exemplary cigarettes). As shouldbe expected, the quantity of glycerin in the TPM increases with theaddition of glycerin in the cigarette filler. However, as illustrated inFIG. 6A, even though the quantity of glycerin in TPM increases with theaddition of the glycerin-impregnated silica, no significant change inthe transfer percentage of glycerin for the 11-mg tar exemplarycigarettes (see A-02 and A-03 as compared with the A-01) can be seen. Inaddition, with respect to the 6-mg tar exemplary cigarettes, asillustrated in FIG. 6B, the transfer percentage of glycerin decreaseswith the addition of glycerin-impregnated silica.

Additionally, the use of activated carbon sorbent in a filter of thecigarette can also affect the TPM (and glycerin transfer). Asillustrated in FIG. 6A and FIG. 6B, the 11-mg tar and the 6-mg tarexemplary cigarettes display a decrease in the quantity of glycerin inTPM as well as the percent glycerin transfer when activated carbon isremoved or replaced with cellulose acetate filter (for example, see A-02compared with A-06 and A-08).

The TPM, tar, nicotine, water and glycerin for the same exemplarycigarettes from Table 3 and FIGS. 6A and 6B are set forth on a puffbasis in Table 4, FIG. 7A and FIG. 7B.

TABLE 4 TPM, Tar, water, nicotine and glycerin per puff Puff TPM/puff¹Tar/puff² Nic/puff Wat./puff Gly./puff S-tar/puff³ Cigarette Cig. CodeCigarette Description Count (mg/puff) (mg/puff) (mg/puff) (mg/puff)(mg/puff) (mg/puff) 11-mg A-01 Control (8 mm C-Beads in Filter) 6.2 1.841.52 0.12 0.21 0.17 1.35 tar A-02 110 mg (Silica + glycerin) in filler8.2 1.71 1.37 0.09 0.26 0.58 0.78 A-03 220 mg (Silica + glycerin) infiller 9.7 1.43 1.14 0.06 0.22 0.72 0.42 A-04  50 mg (Silica only) infiller 7.2 1.26 1.03 0.09 0.15 0.13 0.90 A-05 100 mg (Silica only) infiller 8.5 0.99 0.81 0.07 0.11 0.10 0.71 A-06 110 mg (Silica + glycerin)in filler, no 8.4 2.14 1.68 0.10 0.36 0.38 1.30 carbon and empty cavityin filter A-07 220 mg (Silica + glycerin) in filler, no 10.2 1.27 0.990.07 0.21 0.35 0.64 carbon and empty cavity in filter A-08 110 mg(Silica + glycerin), carbon replaced 8.7 1.60 1.28 0.08 0.24 0.27 1.01by CA A-09 220 mg (Silica + glycerin), carbon replaced 9.8 1.35 1.090.07 0.20 0.31 0.78 by CA  6-mg B-01 Control (8 mm C-Beads in Filter)6.7 0.91 0.60 0.11 0.19 0.09 0.50 Tar B-02 110 mg (Silica + glycerin) infiller 9.7 0.59 0.47 0.04 0.08 0.14 0.33 B-03 220 mg (Silica + glycerin)in filler 11.3 0.41 0.32 0.03 0.06 0.15 0.17 B-04  50 mg (Silica only)in filler 8.0 0.58 0.46 0.05 0.06 0.06 0.40 B-05 100 mg (Silica only) infiller 8.9 0.39 0.31 0.03 0.05 0.04 0.27 B-06 110 mg (Silica + glycerin)in filler, no 9.9 0.62 0.51 0.04 0.07 0.11 0.40 carbon and empty cavityin filter B-07 220 mg (Silica + glycerin) in filler, no 12.1 0.39 0.310.02 0.05 0.09 0.23 carbon and empty cavity in filter B-08 110 mg(Silica + glycerin), carbon replaced 9.3 0.53 0.43 0.03 0.06 0.10 0.33by CA B-09 220 mg (Silica + glycerin), carbon replaced 11.8 0.35 0.290.02 0.05 0.07 0.22 by CA ¹TPM numbers listed here were collected in theexperiments for the analyses of tar, nicotine and water. TPM used forthe measurement of glycerin concentration were collected in separateexperiments and are not listed in the table. ²Glycerin is included intar. ³Smoke tar is equal to tar minus glycerin.

With the exception of A-06 in FIG. 7A, the TPM/puff, tar/puff andnicotine/puff levels all decreased when either silica orglycerin-impregnated silica is added in the tobacco rod. As illustratedin FIG. 7A, the glycerin/puff of the 11-mg tar exemplary cigarettesincreases as the glycerin-containing silica is added in the tobacco rod.This effect is less significant for the 6-mg tar exemplary cigarettes,as illustrated in FIG. 7B, probably due to the increased ventilation, asdiscussed above. The water/puff did not appear to change correspondinglywith the nicotine/puff, which while not wishing to be bound by theory,is believed to be attributable to an increase in the amount of water inthe tobacco rod due to the hygroscopic (water absorbing) nature ofglycerin.

Tar, nicotine, water and glycerin for the same selected exemplarycigarettes were also measured based upon a TPM basis are shown in Table5.

TABLE 5 Tar, water, nicotine and glycerin on TPM basis Puff TPM¹Tar/TPM² Nic./TPM Wat./TPM Gly./TPM S-Tar/TPM⁴ Cigarette Cig. CodeCigarette Description Count (mg/cigt) (mg/mg) (mg/mg) (mg/mg) (mg/mg)(mg/mg) 11-mg A-01 Control (8 mm C-Beads in Filter) 6.2 11.40 0.82 0.070.11 0.09 0.73 tar A-02 110 mg (Silica + glycerin) in filler 8.2 14.000.80 0.05 0.15 0.34 0.46 A-03 220 mg (Silica + glycerin) in filler 9.713.90 0.80 0.05 0.16 0.50 0.29 A-04  50 mg (Silica only) in filler 7.29.10 0.81 0.07 0.12 0.10 0.71 A-05 100 mg (Silica only) in filler 8.58.40 0.82 0.07 0.11 0.10 0.72 A-06 110 mg (Silica + glycerin) in filler,no 8.4 18.00³ 0.78 0.05 0.17 0.17 0.61 carbon and empty cavity in filterA-07 220 mg (Silica + glycerin) in filler, no 10.2 12.93³ 0.78 0.05 0.160.28 0.50 carbon and empty cavity in filter A-08 110 mg (Silica +glycerin), carbon replaced 8.7 13.97 0.80 0.05 0.15 0.17 0.63 by CA A-09220 mg (Silica + glycerin), carbon replaced 9.8 13.30 0.81 0.05 0.150.23 0.57 by CA  6-mg B-01 Control (8 mm C-Beads in Filter) 6.7 6.100.66 0.12 0.21 0.10 0.55 Tar B-02 110 mg (Silica + glycerin) in filler9.7 5.70 0.81 0.07 0.13 0.24 0.56 B-03 220 mg (Silica + glycerin) infiller 11.3 4.60 0.78 0.06 0.15 0.36 0.42 B-04  50 mg (Silica only) infiller 8.0 4.60 0.80 0.08 0.11 0.11 0.70 B-05 100 mg (Silica only) infiller 8.9 3.50 0.80 0.08 0.12 0.11 0.69 B-06 110 mg (Silica + glycerin)in filler, no 9.9 6.10 0.82 0.06 0.12 0.17 0.65 carbon and empty cavityin filter B-07 220 mg (Silica + glycerin) in filler, no 12.1 4.67 0.810.06 0.13 0.22 0.58 carbon and empty cavity in filter B-08 110 mg(Silica + glycerin), carbon replaced 9.3 4.93 0.82 0.06 0.12 0.19 0.63by CA B-09 220 mg (Silica + glycerin), carbon replaced 11.8 4.17 0.820.06 0.13 0.20 0.62 by CA ¹TPM numbers listed here were collected in theexperiments for the analyses of tar, nicotine and water. TPM used forthe measurement of glycerin concentration were collected in separateexperiments and are not listed in the table. ²Glycerin is included intar. ³The difference between the TPM here and the TPM obtained in theexperiments for the glycerin analysis is statistically significant. ⁴Tarexcluding glycerin.

As shown in Table 5, the glycerin/TPM appears to increase significantlyfor A-02 and A-03 compared to the control A-01. The increase inglycerin/TPM appears to be less significant for the 6-mg tar exemplarycigarettes (B-02 and B-03 as compared with B-01) possibly due toincreased ventilation, as discussed above. Table 5 also lists the valuesof tar from cigarette smoke per TPM (S-Tar/TPM). Again, a significantdecrease in S-Tar/TPM for A-02 and A-03 can be observed as compared tothe control A-01 possibly due to the dilution of glycerin while a lesssignificant decrease in S-Tar/TPM for B-02 and B-03 is observed possiblydue to the increased ventilation. The level of nicotine/TPM also appearsto decrease when either silica or glycerin-silica is added in thetobacco rod.

Table 6 shows the carbonyls in gas vapor phase (GVP) on a TPM basis forthe same selected exemplary cigarettes, while Table 7 shows the percentchange in the carbonyls vs. the exemplary control cigarettes.

TABLE 6 Carbonyls per TPM Formal- Acetal- Propion- Crotonal- MEKButyral- Cig. dehyde dehyde Acetone Acrolein aldehyde dehyde (μg/ dehydeCigarette Code Cigarette Description (μg/mg) (μg/mg) (μg/mg) (μg/mg)(μg/mg) (μg/mg) mg) (μg/mg) 11-mg A-01 Control (8 mm C-Beads in 2.6330.93 12.84 2.75 1.79 0.81 3.42 1.63 tar A-02 110 mg (Silica + glycerin)1.88 19.94 7.86 4.45 1.56 0.41 1.74 1.29 in filler A-03 220 mg (Silica +glycerin) 1.67 20.39 8.16 7.67 1.97 0.36 1.17 0.74 in filler A-04  50 mg(Silica only) in filler 2.28 30.23 13.02 4.66 2.03 0.69 3.42 1.45 A-05100 mg (Silica only) in filler 1.68 26.62 11.26 6.20 2.23 0.63 2.69 1.07 6-mg B-01 Control (8 mm C-Beads in 1.91 31.48 15.80 2.76 2.18 0.58 3.662.04 tar B-02 110 mg (Silica + glycerin) 1.68 28.66 14.16 4.50 2.13 1.033.97 1.61 in filler B-03 220 mg (Silica + glycerin) 1.36 19.48 10.266.77 1.87 0.22 1.43 0.58 in filler B-04  50 mg (Silica only) in filler1.27 27.69 14.16 5.33 2.12 0.53 2.71 1.23 B-06 100 mg (Silica only) infiller 1.92 36.16 20.99 7.19 3.34 1.04 3.32 1.89

TABLE 7 Percent change in Carbonyls per TPM vs. control Formal- Acetal-Propion- Crotonal- Butyral- dehyde dehyde Acetone Acrolein aldehydedehyde MEK dehyde Cig. (% (% (% (% (% (% (% (% Cigarette Code CigaretteDescription Change) Change) Change) Change) Change) Change) Change)Change) 11-mg A-01 Control (8 mm C-Beads in Filter) 0.00 0.00 0.00 0.000.00 0.00 0.00 0.00 tar A-02 110 mg (Silica + glycerin) −26.74 −35.53−38.84 61.46 −13.20 −49.01 −49.10 −20.92 in filler A-03 220 mg (Silica +glycerin) −37.82 −34.07 −36.44 174.7 10.26 −57.00 -66.86 −54.70 infiller A-04  50 mg (Silica only) in filler −9.89 −2.27 1.37 66.42 13.41−14.07 −0.04 −10.90 A-05 100 mg (Silica only) in −37.67 −13.94 −12.42125.2 26.00 −34.89 −24.33 −34.37  6-mg B-01 Control (8 mm C-Beads inFilter) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 tar B-02 110 mg(Silica + glycerin) −17.01 −8.95 −10.42 63.83 −2.34 76.77 11.70 −21.44in filler B-03 220 mg (Silica + glycerin) −28.62 −38.11 −36.05 146.2−14.24 −62.46 −69.70 −71.50 in filler B-04  50 mg (Silica only) infiller −33.27 −12.34 −10.41 93.83 −2.88 −9.29 −23.79 −39.85 B-05 100 mg(Silica only) in 0.36 11.67 32.90 161.4 53.13 78.59 −6.59 −7.81

For both 11-mg tar and 6-mg tar exemplary cigarettes, as shown in Tables6 and 7, a decrease in formaldehyde in GVP can be found for all theexemplary cigarettes compared to the control. While not wishing to bebound by theory, it is believed that the reduction of formaldehyde maybe due to the addition of silica gel alone in the tobacco rod.

Table 8 shows the volatile organic compounds (VOC) in GVP on a TPM basisfor the selected exemplary cigarettes, and Table 9 shows the percentchange in the VOC vs. exemplary control cigarettes.

TABLE 8 VOC per TPM 1,3-Butadiene Isoprene Benzene Acrylonitrile TolueneStyrene Cigarette Cig. Code Cigarette Description (μg/mg) (μg/mg)(μg/mg) (μg/mg) (μg/mg) (μg/mg) 11-mg A-01 Control (8 mm C-Beads inFilter) 1.08 10.08 1.15 0.29 1.95 0.20 tar A-02 110 mg (Silica +glycerin) in 0.88 6.80 0.83 0.21 1.32 0.13 A-03 220 mg (Silica +glycerin) in 0.87 6.57 0.79 0.20 1.23 0.12 A-04  50 mg (Silica only) in1.18 9.58 1.10 0.28 1.72 0.17 A-05 100 mg (Silica only) in filler 1.179.20 1.19 0.29 1.90 0.19  6-mg B-01 Control (8 mm C-Beads in Filter)1.17 11.03 1.36 0.28 2.38 0.17 tar B-02 110 mg (Silica + glycerin) in0.99 7.64 1.05 0.23 1.80 0.13 B-03 220 mg (Silica + glycerin) in 0.796.14 0.82 0.19 1.38 0.10 B-04  50 mg (Silica only) in 1.03 8.28 1.070.24 1.74 0.13 B-05 100 mg (Silica only) in filler 1.05 8.17 1.07 0.241.75 0.15

TABLE 9 Percent change in VOC per TPM vs. control 1,3-Butadiene IsopreneBenzene Acrylonitrile Toluene Styrene Cigarette Cig. Code CigaretteDescription (% Change) (% Change) (% Change) (% Change) (% Change) (%Change) 11-mg A-01 Control (8 mm C-Beads in Filter) 0.00 0.00 0.00 0.000.00 0.00 tar A-02 110 mg (Silica + glycerin) in −18.90 −32.52 −27.57−27.99 −32.14 −36.88 A-03 220 mg (Silica + glycerin) in −19.54 −34.77−31.30 −30.75 −36.80 −42.54 A-04  50 mg (Silica only) in 9.65 −4.89−4.04 −5.30 −11.58 −17.49 A-05 100 mg (Silica only) in filler 8.17 −8.673.70 −1.80 −2.59 −7.60  6-mg B-01 Control (8 mm C-Beads in Filter) 0.000.00 0.00 0.00 0.00 0.00 tar B-02 110 mg (Silica + glycerin) in −15.37−30.75 −22.60 −17.05 −24.57 −25.80 B-03 220 mg (Silica + glycerin) in−32.29 −44.29 −39.72 −33.11 −42.15 −39.93 B-04  50 mg (Silica only) in−12.07 −24.92 −21.58 −16.09 −26.76 −23.80 B-05 100 mg (Silica only) infiller −10.23 −25.88 −21.76 −15.26 −26.32 −15.00

As shown in Tables 8 and 9, a decrease in VOC is observed for exemplarycigarettes A-02, A-03, B-02 and B-03 compared to their controlcounterparts, implying that the inclusion of glycerin in the filler doesnot contribute to the VOC present in mainstream smoke.

Table 10 shows the polycyclic aromatic hydrocarbons (PAHs) in particularphase on a TPM basis for the selected exemplary cigarettes. Table 11shows the percent change in the PAHs vs. exemplary control cigarettes.

TABLE 10 PAHs per TPM Puff TPM B[a]A/TPM B[a]P/TPM Cigarette Cig. CodeCigarette Description Count (mg/cigt) (ng/mg) (ng/mg) 11-mg A-01 Control(8 mm C-Beads in Filter) 6.23 12.23 0.76 0.49 tar A-02 110 mg (Silica +glycerin) 8.17 14.37 1.17 0.80 in filler A-03 220 mg (Silica + glycerin)9.73 14.53 1.38 0.95 in filler A-04  50 mg (Silica only) in filler 7.2310.37 1.19 0.77 A-05 100 mg (Silica only) in filler 8.03 8.60 1.72 1.12 6-mg B-01 Control (8 mm C-Beads in Filter) 7.57 6.63 0.87 0.60 tar B-02110 mg (Silica + glycerin) 9.20 6.87 1.16 0.78 in filler B-03 220 mg(Silica + glycerin) 10.77 5.63 1.37 0.91 in filler B-04  50 mg (Silicaonly) in filler 7.87 4.97 1.83 1.18 B-05 100 mg (Silica only) in filler8.77 3.53 2.83 1.76

TABLE 11 Percent change in PAHs per TPM vs. control Puff TPM B[a]A B[a]PCigarette Cig. Code Cigarette Description Count (mg/cigt) (% change) (%change) 11-mg A-01 Control (8 mm C-Beads in Filter) 6.23 12.23 0.00 0.00tar A-02 110 mg (Silica + glycerin) 8.17 14.37 53.85 62.70 in fillerA-03 220 mg (Silica + glycerin) 9.73 14.53 81.38 92.47 in filler A-04 50 mg (Silica only) in filler 7.23 10.37 56.24 57.12 A-05 100 mg(Silica only) in filler 8.03 8.60 126.09 127.49  6-mg B-01 Control (8 mmC-Beads in Filter) 7.57 6.63 0.00 0.00 tar B-02 110 mg (Silica +glycerin) 9.20 6.87 32.32 29.56 in filler B-03 220 mg (Silica +glycerin) 10.77 5.63 56.42 61.80 in filler B-04  50 mg (Silica only) infiller 7.87 4.97 109.51 96.14 B-05 100 mg (Silica only) in filler 8.773.53 224.08 192.86

As shown above in Tables 10 and 11, the modified exemplary cigarettesshowed increases in PAHs compared to their control counterparts. For theexemplary cigarettes A-04, A-05, B-04 and B-05, adding plain silica intothe tobacco increases the PAHs in the particular phase. For theexemplary cigarettes A-02, A-03, B-02 and B-03, a combination of twoopposite effects of glycerin and silica gel on PAHs (which might becompeting) appears to be shown.

The tobacco specific nitrosamines (TSNAs) on a TPM basis and the percentchange in the TSNA vs. exemplary control cigarettes are shown in Table12 and Table 13, respectively.

TABLE 12 TSNAs per TPM Puff TPM NNN/TPM NNK/TPM NAT/TPM NAB/TPMCigarette Cig. Code Cigarette Description Count (mg/cigt) (ng/mg)(ng/mg) (ng/mg) (ng/mg) 11-mg A-01 Control (8 mm C-Beads in Filter) 6.1312.10 6.07 4.22 5.77 0.81 tar A-02 110 mg (Silica + glycerin) 8.03 14.474.66 3.12 4.36 0.59 in filler A-03 220 mg (Silica + glycerin) 9.70 14.503.88 2.67 3.57 0.46 in filler A-04  50 mg (Silica only) in filler 7.2010.77 6.76 4.52 5.95 0.84 A-05 100 mg (Silica only) in filler 7.87 8.876.72 4.18 6.42 0.91  6-mg B-01 Control (8 mm C-Beads in Filter) 6.606.63 5.79 4.22 4.95 0.75 tar B-02 110 mg (Silica + glycerin) 8.97 6.404.53 2.99 4.05 0.57 in filler B-03 220 mg (Silica + glycerin) 11.23 5.403.72 2.48 3.31 0.42 in filler B-04  50 mg (Silica only) in filler 7.374.43 6.97 4.31 5.92 0.83 B-05 100 mg (Silica only) in filler 8.30 3.407.22 4.25 6.58 0.85

TABLE 13 Percent change in TSNAs per TPM vs. control Puff TPM NNN/TPMNNK/TPM NAT/TPM NAB/TPM Cigarette Cig. Code Cigarette Description Count(mg/cigt) (% change) (% change) (% change) (% change) 11-mg A-01 Control(8 mm C-Beads in Filter) 6.13 12.10 0.00 0.00 0.00 0.00 tar A-02 110 mg(Silica + glycerin) 8.03 14.47 −23.19 −26.13 −24.42 −27.13 in fillerA-03 220 mg (Silica + glycerin) 9.70 14.50 −36.02 −36.69 48.25 −43.99 infiller A-04  50 mg (Silica only) in filler 7.20 10.77 11.36 6.96 3.053.24 A-05 100 mg (Silica only) in filler 7.87 8.87 10.70 −0.92 11.2712.41  6-mg B-01 Control (8 mm C-Beads in Filter) 6.60 6.63 0.00 0.000.00 0.00 tar B-02 110 mg (Silica + glycerin) 8.97 6.40 −21.88 −29.18−18.24 −23.48 in filler B-03 220 mg (Silica + glycerin) 11.23 5.40−35.76 −41.21 −33.16 −43.94 in filler B-04  50 mg (Silica only) infiller 7.37 4.43 20.30 2.06 19.55 11.46 B-05 100 mg (Silica only) infiller 8.30 3.40 24.54 0.57 32.90 13.93

As shown in Tables 12 and 13, the TSNAs decrease for the exemplarycigarettes A-02, A-03, B-02 and B-03 compared to the exemplary controlcigarettes, but increase for the exemplary cigarettes A-04, A-05, B-04and B-05 compared to the control. Again, the TSNA values of A-02, A-03,B-02 and B-03 may result from the competing effects of silica andglycerin on the TSNA in particular phase.

The phenolic compounds on a TPM basis and their change vs. exemplarycontrol cigarettes are listed in Table 14 and Table 15, respectively.

TABLE 14 Phenolics Per TPM Hydro- quinone Resorcinol Catechol Phenolp-Cresol m-Cresol o-Cresol Puff TPM per TPM per TPM per TPM per TPM perTPM per TPM per TPM Cigarette Cig. Code Cigarette Description Count(mg/cigt) (μg/mg) (μg/mg) (μg/mg) (μg/mg) (μg/mg) (μg/mg) (μg/mg) 11-mgA-01 Control (8 mm C-Beads in Filter) 6.13 12.10 3.21 0.14 2.88 0.900.47 0.24 0.21 tar A-02 110 mg (Silica + glycerin) in 8.03 14.47 2.320.08 1.97 0.36 0.18 0.06 0.09 filler A-03 220 mg (Silica + glycerin) in9.70 14.50 1.88 0.06 1.59 0.21 0.10 0.03 0.06 filler A-04  50 mg (Silicaonly) in filler 7.20 10.77 3.49 0.12 2.99 0.71 0.35 0.20 0.18 A-05 100mg (Silica only) in filler 7.87 8.87 3.74 0.12 2.94 0.43 0.26 0.12 0.10 6-mg B-01 Control (8 mm C-Beads in Filter) 6.60 6.63 3.27 0.12 3.020.69 0.36 0.18 0.17 tar B-02 110 mg (Silica + glycerin) in 8.97 6.402.38 0.06 2.08 0.17 0.05 N.D. 0.03 filler B-03 220 mg (Silica +glycerin) in 11.23 5.40 2.17 0.04 1.81 0.09 N.D. N.D. N.D. filler B-04 50 mg (Silica only) in filler 7.37 4.43 4.42 0.11 3.74 0.43 0.18 0.110.09 B-05 100 mg (Silica only) in filler 8.30 3.40 4.47 0.12 3.32 0.12N.D. N.D. N.D.

TABLE 15 Percent change in phenolics per TPM vs. control Hydro- Phenolquinone Resorcinol Catechol per p-Cresol m-Cresol o-Cresol TPM per TPMper TPM per TPM TPM per TPM per TPM per TPM Cig. Puff (mg/ (% (% (% (%(% (% (% Cigarette Code Cigarette Description Count cigt) change)Change) change) change) change) change) change) 11-mg A-01 Control (8 mmC-Beads in Filter) 6.13 12.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 tarA-02 110 mg (Silica + glycerin) in 8.03 14.47 −27.78 −45.88 −31.50−60.10 −61.85 −74.04 −58.18 filler A-03 220 mg (Silica + glycerin) in9.70 14.50 −41.29 −60.73 −44.61 −76.27 −78.04 −85.61 −74.32 filler A-04 50 mg (Silica only) in filler 7.20 10.77 8.91 −14.06 3.99 −21.64 −25.08−14.74 −17.87 A-05 100 mg (Silica only) in filler 7.87 8.87 16.77 −11.702.35 −52.42 −44.93 −48.24 −52.76  6-mg B-01 Control (8 mm C-Beads inFilter) 6.60 6.63 0.00 0.00 0.00 0.00 0.00 0.00 0.00 tar B-02 110 mg(Silica + glycerin) in 8.97 6.40 −27.40 −48.18 −31.08 −75.22 −87.04N.A.¹ −81.16 filler B-03 220 mg (Silica + glycerin) in 11.23 5.40 −33.77−69.29 −39.81 −86.65 N.A.¹ N.A.¹ N.A.¹ filler B-04  50 mg (Silica only)in filler 7.37 4.43 35.14 −6.48 24.19 −38.20 −50.13 −37.66 −45.59 B-05100 mg (Silica only) in filler 8.30 3.40 36.66 −2.45 10.23 −83.03 N.A.¹N.A.¹ N.A.¹

As shown in Tables 14 and 15, significant reduction in phenolic levelscan be achieved through the addition of either plain silica orglycerin-impregnated silica into the tobacco rod.

In summary, it appears that the addition of glycerin-impregnated silicain a tobacco rod can appreciably have an effect on constituents intobacco smoke including PAHs, TSNAs and phenolics. Thus, immobilizeddiluents, such as glycerin-impregnated silica, appear to be able to havebeneficial properties for smoking.

While the invention has been described in detail with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modification may be made, and equivalentsthereof employed, without departing from the scope of the claims.

The invention claimed is:
 1. A method of making a cigarette, comprising:forming immobilized diluents by incorporating diluents in sorbentmaterials; mixing the immobilized diluents with tobacco cut filler;forming a tobacco rod from the tobacco cut filler with the immobilizeddiluents mixed therein; and attaching the tobacco rod to a filter,wherein the diluent comprises an aerosol forming agent and the sorbentcomprises a porous material with a surface area of at least 50 m2/g,and/or wherein the sorbent has a pore volume of about 0.2 cc/g to about1.5 cc/q.
 2. The method of claim 1, wherein the forming immobilizeddiluents step comprises: heating the sorbent materials and the diluentsin a sealed container to impregnate liquid diluents in sorbentmaterials.
 3. The method of claim 1, wherein the forming immobilizeddiluents step comprises: placing sorbent particulate in a vessel withliquid diluents therein; and incorporating the liquid diluents in thesorbent particulate via absorption and/or adsorption by the sorbentparticulate.
 4. The method of claim 3, wherein the immobilized diluentsare formed by contacting sorbent particles with the diluent,pressurizing and/or heating the sorbent and diluent until the sorbent isloaded with the diluent in an amount ranging from about 60 wt. % toabout 120 wt. %.
 5. The method of claim 1, wherein the sorbent materialcomprises a rounded, spherically-shaped particle, wherein the particleis about 0.05 mm to about 2 mm in a transverse dimension, wherein theparticle is capable of releasing the diluent at temperatures at or above180° C., and/or wherein the immobilized diluent comprises up to 120weight % diluent with respect to the weight of the sorbent.
 6. Themethod of claim 1, wherein the sorbent comprises silica gels, molecularsieves, activated carbons, polymeric porous materials, or combinationsthereof; and/or wherein the sorbent has a surface area of about 100 m²/gto about 1000 m²/g.
 7. The method of claim 1, wherein the diluentcomprises glycerin, propylene glycol, triacetin, triethylene glycol,triethyl citrate, or combinations thereof, and/or wherein the sorbentcomprises silica gels, molecular sieves, activated carbons, polymericporous materials, or combinations thereof.
 8. A method of making acigarette, comprising: forming immobilized diluents by incorporatingdiluents in sorbent materials: mixing the immobilized diluents withtobacco cut filler; forming a tobacco rod from the tobacco cut fillerwith the immobilized diluents mixed therein; and attaching the tobaccorod to a filter, wherein the sorbent comprises silica gel, the diluentcomprises glycerin and/or propylene glycol, and the glycerin and/orpropylene glycol is loaded into the silica gel at 60% to 120 wt % of thesilica gel.
 9. The method of claim 1, further comprising coating asurface of the sorbent such that the coating further immobilizes thediluent absorbed and/or adsorbed in the sorbent.
 10. A method of makinga cigarette, comprising: forming immobilized diluents by incorporatingdiluents in sorbent materials; mixing the immobilized diluents withtobacco cut filler; forming a tobacco rod from the tobacco cut fillerwith the immobilized diluents mixed therein; and attaching the tobaccorod to a filter, wherein the sorbent consists essentially of silica gel,molecular sieves, activated carbon, or combinations thereof.
 11. Themethod of claim 1, wherein the filter contains a second sorbent, thesecond sorbent comprising a material different than the material of thefirst sorbent.
 12. The method of claim 11, wherein second sorbentincludes a diluent impregnated therein.
 13. The method of clam 1,wherein the cigarette comprises about 1 to about 300 mg of immobilizeddiluents.
 14. The method of claim 1, wherein the cigarette comprisesabout 1 to about 40 wt % diluents.
 15. The method of claim 1, whereinthe cigarette comprises about 10 to about 30 wt % diluents.